The entire film unfolds in a similar vein. The pharmaceutical industry is portrayed as the enemy of the vulnerable; unscrupulous profiteers who will leech the last franc, dinar, and naira from poor African governments, while using their citizens as guinea-pigs for dangerous experiments. As one character puts it: â€œBig pharmaceuticals are up there with arms dealers.â€

The Constant Gardener is bound to be immensely successful. Despite affecting performances by Fiennes and Rachel Weisz, as well as some stunning camera work in Kenya, this will be in no small part due to a script that, with all the subtlety of Michael Moore, tears into everyoneâ€™s favourite villains. We hate Big Pharma because they are the pros in the field where we feel most vulnerable â€” our health. We hate them because they will allow us access to their panaceas only if we cough up. We also hate them (and certainly this is a theme in both novel and film) because they are predominantly American â€” only three of the top 25 best-selling drugs are manufactured in Europe.

Herceptin, our best weapon against breast cancer; Tamiflu, our best hope against bird flu; the many anti-retrovirals used in the treatment of HIV/Aids â€” we owe them all to the pharmaceutical industry. They may be profit-conscious, but Big Pharma plough back a lot of this profit into funding the research that yields the next generation of miracle cures. Idealists who think that health is a human right, and financial incentives should have nothing to do with it, should consider the consequence of turning the industry into a state enterprise: the Government might make some available drugs far less expensive â€” but will it be able to fund the research necessary for future drugs?

Andrew Sullivan, the journalist and gay activist who co-authored The Pharmaceutical Industry, uses the American experience to explain why there will always be a conflict between innovation and accessibility. â€œLook at pharmaceutical R&D over the past 15 years or so. Most years, it grew at a phenomenal rate of around 12 per cent to 15 per cent, leading to the pharmaceutical miracle we are now experiencing. There are two exceptions, 1993 and 1994, when Hillary Clinton attempted her government takeover and R&D collapsed to around 6 per cent growth. Investors arenâ€™t dumb. They knew what that meant. And they pulled out.â€

Studies, clinical trials, patent applications, acceptance by regulatory bodies and marketing: costly steps are needed before a drug can be put on the market. Does it make sense for government to undertake them, diverting immense resources from serving the public here and now? Moreover, such state intervention would devastate the poor in the Third World. Most companies can afford to manufacture only products that fight the diseases of the poor by investing some of the gains they make in selling treatments for the diseases of the rich.

Put a lid on prices for Prozac, Viagra and other drugs that address the concerns of the rich world, and pretty soon you have dried up the capital necessary to manufacture a cure for TB, malaria and elephantiasis.

Indeed, although to admit it would offend the liberals who will lap up The Constant Gardener, pharmaceutical giants have often acted heroically in Africa â€” only to find their efforts sabotaged by local governments. Novartis recently proposed to sell Coartem, its anti-malarial drug, at cost through the World Health Organisation. There was no take-up: for several African leaders, the malaria debilitating thousands of poorer citizens was simply not a priority. Two years ago several fanatical Islamic preachers in Kano, northern Nigeria, warned their followers to boycott the polio vaccine that was to be distributed, free, to all children: it was, the imams insisted, part of a Western plot against Muslims. Everyone knows of South Africaâ€™s reluctance to acknowledge publicly its Aids epidemic â€” and the resulting fatal delay in striking a deal with the manufacturers of available treatments.